ACTINOBACILLUS INFECTIONS
STEPHANIE SPECK
Bundeswehr Institute of Microbiology, Department of Virology and Rickettsiology, Munich, Germany
Members of the genus A ctinobacillus, family Pasteurel- laceae, are small (0.3—0.5 ? 0.6—1.4 μm), Gram-negative, pleomorphic rods or coccobacilli that are facultatively anaerobic, non-motile and non-spore-forming.
All Actinobacillus isolates have complex nutritional requirements. There are two biotypes of Actinobacillus pleuropneumoniae (APP), differentiated on the basis of their nicotinamide adenine dinucleotide (NAD) requirement. Thirteen serotypes of biotype 1 and 6 serotypes or biotype 2 have been described. In Europe, serotypes 2 and 9 are most often found.Species within the genus Actinobacillus are always associated with mucous membranes. Actinobacillus pleuropneumoniae is considered an obligate parasite of the porcine respiratory tract and is the aetiological agent of porcine pleuropneumonia (synonyms: infectious pleuropneumonia of swine, Haemophilus contagious pleuropneumonia), a highly contagious and economically significant respiratory disease in domestic swine worldwide. Transmission occurs via aerosols or direct contact with infected pigs, and the organism does not survive for long in the environment. Actinobacillus Iignieresii is a commensal of the ruminant oropharynx and rumen and the oral cavity of healthy horses. In ruminants it causes ‘wooden tongue’, which consists of chronic inflammatory lesions, forming fibropu- rulent masses in the tongue and other oropharyngeal soft tissues, but it has also been associated with pyemic processes of soft tissues and stomatitis in horses.
APP seroprevalence in wild boar ( Sus scrofa) in Slovenia has been reported1-74), and A. minor and A. indolicus were isolated from nasal swabs of wild boar in northeastern Spain(75). Data regarding prevalence and distribution of this agent among free-ranging wild boar are scarce. In the study in Slovenia, a serological survey was performed on wild boars shot during the hunting season. Of 178 samples tested, 52% produced positive results for antibodies against APP using the Chekit APP-ApxIV enzyme immunoassay kit (Bommeli Diagnostics, Bern, Switzerland)1-74).
Clinical disease or lesions related to Actinobacillus spp. infection have not been described in wildlife in Europe. Some APP serotypes are more virulent than others but all are capable of causing pleuropneumonia; hence studies on wild boar isolates are needed to clarify their pathogenicity and significance in free-ranging European wild-boar populations.